1. Field of the Invention
The present invention relates to mixed hook/loop separable fasteners, and more specifically to mixed hook/loop fasteners comprising hook-like fastening elements and loop-like fastening elements, the height of the latter being larger than that of the former, which are arranged adjacent each other on one surface of a base fabric.
2. Description of the Prior Art
Known two-component separable fasteners consist of a male fastener component comprising a base fabric provided on one surface thereof with a multiplicity of hook-like fastening elements comprising synthetic monofilament or shaped plastic projections having a swollen head and a female fastener component comprising a base fabric provided on one surface thereof with a multiplicity of loop-like fastening elements. The engagement of these two multiplicity of fastening elements can closely and integrally adhere the two fastener components, which are readily separable by hand.
These two-component fasteners however should carefully be distinguished from each other when being attached for example to wears. If a male fastener component has been, by mistake, attached to a position where a female fastener component should have been attached, the male fastener component cannot engage with the counterpart male fastener component and hence either one of these male fastener components should once again be removed and replaced by a female fastener component. If the male fastener component had been attached with a hot-melt adhesive or the like to the wear, the replacement is practically impossible. If it had been sewn with a sewing machine, the replacement, although possible, requires a time-consuming work.
On the other hand, mixed hook/loop separable fasteners comprising a base fabric provided on one surface thereof with both fastening elements have been proposed against the usual two-component separable fasteners. Thus, for example Japanese Patent Publication No. 12952/1970 and Japanese Patent Application Laid-open No. 2649/1974 disclose a mixed hook/loop separable fastener comprising a base fabric provided on one surface thereof with a multiplicity of hook-like fastening elements and a multiplicity of loop-like fastening elements, both comprising a synthetic monofilament and positioned intermixedly with each other; and Japanese Patent Application Laid-open No. 33745/1974 discloses a similar fastener comprising a base fabric provided on one surface thereof with a mixture of a multiplicity of plastic projections having a swollen head and a multiplicity of loop-like fastening elements. These separable fasteners use 2 sheets of one and the same type or "component", which comprises on its one surface both hook-like fastening elements and loop-like fastening elements intermixedly, the 2 sheets being integrally attachable to and separable from each other.
While these mixed hook/loop separable fasteners have the advantage of using only one type of fastener component, two pieces of which are attachable to and separable from each other, some problems still occur when they are used. That is, since conventional mixed hook/loop separable fasteners comprise hook-like elements the height of which is 25 to 50% larger than that of loop-like elements, such mixed-type fasteners tend, when not engaged with the counterpart, to engage with and damage, because of the hook-like elements present thereon, those textiles that contact them, such as nonwovens, knitted fabrics, napped fabrics or thin woven fabrics. Besides, such fasteners readily pick up broken or waste threads and naps from the textiles with which they contact. Further they had the same drawback as that of the male fastener components, that they deteriorate the hand of wears or the like to which they are attached, because of their course surface feeling.
To make matters worse, the tensile strength and peeling strength (hereinafter inclusively referred to as "engaging strength") when a pair of conventional mixed hook/loop fastener components are attached to each other are significantly lower than those with the combination of the usual male and female fastener components and than a level applicable for practical purposes. This is considered to be due to the fact that, in conventional mixed hook/loop separable fasteners, the density of the hook-like fastening elements and loop-like fastening elements provided on one surface of a base fabric cannot but be very low, and that the ratio of hook-like fastening elements to the total elements is, unavoidably, very small. As a result, no mixed hook/loop separable fasteners have been commercialized on a large scale.